Cruiser-mounted cameras can scan about 700 license plates an hour. We ride along with a cop to learn what automatic scanners know about you.

Of the 32,710 plates that Walczak’s MPH-900 photographed in August, 20 came back as “dirty”—stolen cars, stolen plates, felony warrants, restraining-order violators. Ohio’s database is tailored to ignore petty crimes. “It doesn’t care about expired plates,” Walczak says. “It doesn’t even tell me if a driver has a suspended license. But those 20 stops we made, those are 20 guys we’d never have located without the scanner.” If the 20-per-month average continues, each bonus arrest, over the course of the year, will have cost Maumee taxpayers only $68.

Of course, what sounds like a fantastic bargain may also sound like the jingling handcuffs of Big Brother. The central fallacy about automatic plate readers is that they enable police to automatically track you and your car. Not true. The MPH-900 doesn’t communicate with the DMV, only with a “hot list”—a subset containing the plates of wanted persons. If you aren’t wanted, as we’ve mentioned, your name never comes up because the database doesn’t know a single thing about you. Or about your car. “I’ve never seen one of these hot lists contain any personal information,” says Maloney, “because we’re looking for vehicles associated with people and not looking for the people themselves.” Moreover, the scanners—in Maumee, at least—aren’t being used for revenue enhancement. There’s no particular cash reward for arresting car thieves.

On the other hand, the MPH-900 retains the photographic images of non-wanted “clean” cars, and each of those images includes the time and date it was photographed, plus the GPS coordinates of its location. Were you embarrassingly parked at O’Leary’s Pub at 1 a.m.? The system may have recorded your car there, but it still doesn’t know who you are. And neither does Walczak.

What happens to the thousands of images of non-wanted cars and plates? They’re stored for 30 days in the MPH-900’s central processor, then automatically purged. Of course, if any given police department wishes to save the images ­longer, they can be downloaded remotely. And many departments do precisely that, saving the photos for months or years in the unlikely event that the scanner may have snapped some plates in front of, say, a building that was being burglarized at the time.

Police also have found more proactive uses for the system. “If there’s a homicide,” Walczak explains, “the Toledo police will dispatch a cruiser with a plate reader to the scene as fast as possible, driving up and down to record licenses.” Later, detectives can manually run those plates to determine, for instance, who might have known the victim, who might have had previous criminal contact with the victim, or who had no reason to be in the neighborhood in the first place.

“A family of five was murdered in New York,” recalls Maloney, “and the murder was covered up by arson. A trooper responding to the fire passed the suspects leaving the scene. Their alibi was that they were hundreds of miles away. But the license-plate reader proved they were lying, and they were convicted.” Some critics fear that an officer who has a personal grudge against a civilian might be tempted to input a bogus allegation that would cause an otherwise clean license plate to come up dirty. “But when an officer comes on shift,” counters Maloney, “he’d need to log in to the system with his credentials, and whoever made the bogus entry would be easy to ID.” “What’s more,” adds Walczak, “I can’t falsely tag a guy as being wanted for something ’cause as soon as he’s stopped, they’ll manually run the plate and find out he isn’t. Of course, I could tell the system a certain guy is, say, a ‘possible drug dealer,’ and if the plate got scanned, it might alert another officer to take a closer look. But if he sees no drug-like behavior—if the guy’s just driving along—there’s no violation; there’s nothing to be done.”

Other critics suggest that the scanners prevent a motorist from confronting his accuser, that the accuser is a machine. “In Maumee, that isn’t true,” counters Chief of Police Robert Zink. “You’ll absolutely have a human accuser. He’ll be an officer asking why your license plate belongs to a person wanted for a crime.” And on the subject of stopping motorists without probable cause, Zink asserts that once your license plate has wound up in LEADS, more than enough probable cause exists.

Walczak notes a certain beauty in the system’s relentless objectivity. “It photographs every plate,” he points out. “It doesn’t look for a driver of a certain race, and it doesn’t pick on low-riders or red sports cars.”

Elsag’s plate-reading system is already used by more than 1100 North American law-enforcement agencies, a number that will surely grow. “I think the future of automatic plate readers is they’ll be mounted stationary—on poles,” says Zink. “They’ll be at entrance ramps, busy intersections, and on freeways to catch some interstate action. Since 9/11, pretty much every time you walk into a store or business in America, you’re on camera. I think the day is coming when every time you drive a car on a public road, you’ll be on camera, too.”

Which will make some folks uneasy. And although so far we haven’t heard of scanning systems being abused, there’s certainly room for it. An MPH-900, for example, could scan plates on cars parked in a 30-minute zone—forget about parking meters. If the officer then doubled back in 30 minutes and photographed duplicate plates, well, your ticket is in the mail. On the other hand, it’s not all about evil-doers. One suggested use for license-plate readers is at fast-food outlets. Divulge your plate number and your favorite meal to the local Burger King manager, and next time you come back, he’ll start cooking your Whopper the moment you roll into the lot. The MPH-900 could tag your plate as “that big fat bastard.”